The thickness of the top aluminum (Al) layer on fuses tend to be thick, i.e. about 12,000 xc3x85, because of the mechanical strength requirements for probing and bonding. If the fuse is formed with thick a top Al layer, the yield of the fuse operation, e.g. blowing open by a laser beam, tends to be low.
U.S. Pat. No. 6,261,873 B1 to Bouldin et al. describes a metal fuse with thick and thin segments.
U.S. Pat. No. 6,100,118 to Shih et al. describes a fuse guard ring method and structure.
U.S. Pat. No. 6,100,116 to Lee et al. describes a method to form a protected metal fuse by forming protection layers completely around the fuse.
U.S. Pat. No. 4,792,835 to Sacarisen et al. describes a process for making a metal fuse link in a MOS or CMOS process.
U.S. Pat. No. 6,037,648 to Arndt et al. describes a semiconductor structure including a conductive fuse and a process of fabricating the same.
U.S. Pat. No. 5,936,296 to Park et al. describes integrated circuits having metallic fuse links.
Accordingly, it is an object of one or more embodiments of the present invention to provide improved methods of forming metal fuses.
Other objects will appear hereinafter.
It has now been discovered that the above and other objects of the present invention may be accomplished in the following manner. Specifically, a structure is provided having exposed adjacent metal structures. A patterned dielectric layer is formed over the structure. The patterned dielectric layer having via openings exposing at least a portion of the exposed adjacent metal structures. A metal fuse portion is formed between at least two of the adjacent metal structures without additional photolithography, etch or deposition processes. The metal fuse portion including a portion having a nominal mass and a sub-portion of the portion having a mass less than the nominal mass so that the metal fuse portion is more easily disconnected at the less massive sub-portion during programming of the metal fuse portion.